There's something to be said for familiarity - I work in a Postgres shop now, but spent years operating large MySQL clusters in prior jobs. I'm learning Postgres, but still way more intimately familiar with MySQL (and in particular, InnoDB) internals and would probably reach for it for any new project I were architecting on my own.

Major relational databases generally all do the same stuff in similar ways for the 80% use cases, but when you get into the 20% of weird edge cases, operational concerns at scale, and troubleshooting... really knowing the storage engine internals like the back of your hand is useful.